PROJECT SUMMARY Previous research suggests that habitual short sleep may contribute to problematic weight gain behaviors, such as increased food intake, decreased physical activity and increased time spent engaging in sedentary activities (i.e., computer usage). However, there are methodological concerns about previous longitudinal research which prevent drawing conclusive interpretations. The proposed study is designed to address limitations of previous research and identify future intervention targets for addressing habitual short sleep. Male and female participants (n= 300) will be recruited prior to entering college. Screening and eligibility requirements will be assessed prior to the inclusion in the Time 1 assessment. Participants will complete an additional three assessments over the two year period (i.e., approximately 8, 16 and 24 months after Time 1). Each 1-week monitoring period will include a comprehensive assessment of habitual sleep, physical activity, and body composition using objective measures, a gold standard measure of food consumption, and subjective measures of technology use, and sleep-related beliefs/behaviors.